The present invention relates to a pressure algometer apparatus, and more particularly, to a pressure algometer apparatus for diagnosis of muscle pain or tenderness when subjected to pressure.
Myofascial pain and dysfunction is the most common disorder causing chronic head and neck pain. Traditionally, diagnosis and assessment of the severity of this disorder depends on the tenderness of myofascial tissue at specific locations, often referred to as trigger points, to manual palpation. Manual palpation is accomplished by using one's fingers to apply varying pressure against the trigger points and to observe patient response. However, this technique is often unreliable, due in part to the inability to accurately measure the variation in pressure applied at the trigger point. The present invention solves this and other problems associated with this diagnostic technique.
U.S. Pat. No. 4,337,780 issued to Metrick shows that pressure sensing devices have been used to test muscle strength. The Metrick patent teaches the use of an air tight bag of any suitable configuration depending on the muscle whose strength is to be tested, which is interconnected by tubing to a pressure responsive device so as to form an air tight compartment. The pressure responsive device consists of any suitable device commercially available to measure air pressure, such as a sphygmonanometer. In use, the air tight bag is typically attached to the palm side surface of the distal end of the tester's index finger by an elastic band or the like and/or is attached to the back of the tester's hand.
The Metrick invention is used to test muscle strength and not muscle pain threshold or tenderness. Muscle strength testing devices have long been used. In muscle strength testing, the force applied to the overall muscle is measured. The configuration and consistency of the device used to apply the force is not critical. Therefore, in addition to other differences, there is no teaching or suggestion in Metrick of a pressure sensitive device having a specific configuration and consistency for testing muscle trigger points.
As indicated in a brochure entitled, "Pain and Soft Tissue Pathology Instruments", Pain Diagnostics and Thermography of Great Neck, N.Y. appears to be marketing what are referred to as pain and soft tissue pathology instruments. These instruments apparently utilize a structural column arrangement, possibly a spring biased plunger arrangement, which interconnects a probe end of the instrument to a pressure gauge. In use, the user places the probe end against the tissue to be tested and applies pressure by grasping the gauge housing and forcing the gauge housing toward the probe end, whereupon the pressure is indicated at the pressure gauge. The instrument does not include a pressure probe adapted for positioning at the end of a user's finger and, as a result, does not offer the small size and flexibility of a user's finger in getting at hard to reach places, such as the underside of one's jaw. The pressure gauge is also rigidly attached to the pressure probe which further reduces the flexibility of the instrument.
The present invention solves many of the problems associated with existing algometer devices.